As described in Japanese Unexamined Util. Mod. Application No. S56-095605, Japanese Unexamined Pat. Application No. S62-266212/1987 and U.S. Pat. No. 5,641,255, also known as Japanese Patent Publication H8-004733/1996, hereinafter referred to as Patent Literature Nos. 1, 2 and 3, clips are commonly known which comprise a bushing having a flange and a leg, and a pin with legs that are inserted into the bushing and a flange of larger diameter than the legs, designed so that the legs of the bushing to which the pin is coupled are inserted into holes in a plurality of members being attached to, such as panels, and the pin is further inserted into the bushing to diametrically spread the legs; the plurality of members being attached to are then clamped by the diametrically spread leg portion and flange thereof, and those members being attached to are mutually coupled.
In a clip described in Patent Literature 1, the pin legs are bifurcated. When the pin legs in this bifurcated shape are inserted into the hollow portion of a bushing leg, the pin legs are opened and diametrically spread by a wedge-shaped leg spreader formed at a medium height position in the hollow portion of the bushing leg, the plurality of members being attached to are clamped between the bushing flange and the diametrically spread pin legs, and those members being attached to are mutually coupled. In a clip described in Patent Literature 2, a latching leg that forms a bushing is accommodated inside a divided leg portion of a pin, and at the lower end of the latching leg, a wedge-shaped leg spreader is formed. When the pin legs are inserted into the holes in a plurality of members being attached to, the flange of the head of the latching leg forming the bushing comes up flush against a member being attached to, the insertion of the latching leg inserted together with the pin stops, the pin legs that are being inserted are opened and diametrically spread by the wedge-shaped leg spreader of the bushing (latching leg), the plurality of members being attached to are clamped between the pin flange and the diametrically spread pin leg, and the members being attached to are mutually coupled. With these clips described in Patent Literature 1 and 2, the pin leg is rendered into a diametrically spread condition by the leg spreader of the bushing, so when the coupled condition persists for a long time, the pin leg cannot return to the original closed-leg condition but is thoroughly deformed into the diametrically spread condition. This is believed to be a consequence of the fact that the pin exhibits deformation due to a phenomenon called “stress relaxation.” When deformation caused by stress relaxation occurs, a spring force operates to return the deformation to the original attitude. When the clips of Patent Literature 1 and 2 are reused, for example, an operation must be performed that requires force to return the deformation to the original attitude, time and effort are required for the refastening operation, and, in most cases, reuse or refastening is very difficult.
The clip described in Patent Literature 3 is configured of a plastic bushing which has a flange and legs and is formed so as to be hollow. The bushing legs are inserted into the holes of a plurality of members being attached to such as panels, the pin leg is inserted into the hollow leg of the bushing from the bushing flange end, the bushing legs are then diametrically spread, and the plurality of members being attached to are clamped and mutually coupled by the bushing flange and the diametrically spread bushing leg portion. With the members being attached to in the coupled condition, as described above, the pin leg is inserted into the bushing legs, the tip ends of the bushing legs are maintained in a diametrically spread condition, and that deformation is maintained in the diametrically spread condition by the deformation (called clip deformation in Patent Literature 3) caused by stress relaxation, after a long-term coupling. With the clip of Patent Literature 3, when the bushing legs are formed of a plurality of split pieces, a hole is provided at the tip end of the pin legs for accepting the tip ends of the bushing legs, and the bushing legs are to be pulled out after a long-term coupling, the tip ends of the bushing legs are accepted into the hole at the tip end of the pin legs, the diameter of the diametrically spread bushing leg portion is diametrically compressed while pulling the pin legs out, clip detachment is facilitated, and the deformation caused by the stress relaxation of the bushing legs is handled. With this clip, however, the shape of the tip ends of the pin legs becomes complex because of the hole that is formed for accepting the tip ends of the bushing legs. Furthermore, when the bushing legs are deformed by stress relaxation, acceptance of the tip ends of the bushing legs into the pin leg hole is not guaranteed, so there is a danger of not achieving the desired advantage.
In view of the foregoing, an object of the present invention is to provide a reusable clip which does not require the pin to be of a complex shape and which is capable of overcoming deformation caused by stress relaxation.